Fuel-injection valve for oil-engines



K. O. KELLER.

Patented June 1, 1920.

.ILLLL 1 LLL, L I IL IL L IL LIL II 4 W HE v j F i a 6 z r ma J a h flwwgi W YVA 2 w\ mkfi FUEL INJECTION VALVE FOR OIL ENGINES.- I APPLICATION FILED DEC-9, 191a.

UNITED STATES PATENT OFFICE.

KARL OTTO KELLER, OF SUN DERLAND, ENGLAND, ASSIGNOR OF ONE-HALF TO ROBERT PILE DOXFOBD, OF SUNDERLAND, DURHAM, ENGLAND.

FUEL-INJECTION VALVE FOR OIL-ENGINES.

Specification of Letters Patent.

Patented June 1, 1920.

Application filed December 9, 1918. Serial at; 265,876.

To all whom it may concern:

Be itknown that I, KARL Or'ro KELLER,

'cases are known wherein the packing has prevented the needle-valve from closing the orifice to the cylinder with the result that -the timing of the fuel-injection into the cylinder has been out of control, and the consequences have sometimes proved disastrous. Another objection to the'gland packing is that in replacing the needle-valve, particles of the packing material adhere to the tip of the needle-valve when it is pushed through the gland; these particles become jammed between the needle-valve and its seat, or obstruct the narrow passages through which the fuel has to pass. The needle-valve is usually held against its seat by a spring operating on the valve at the end thereof opposite to the valve-seat, and this spring has had to be strong enough to act as a counterbalance which shall prevent the needle-valve from being blown out by the gas and fuel pressure and shall provide a margin of strength for overcoming gland-friction and inertia forces. In cases where the gas or oil pressures are very high this spring becomes enormous even if the diameter of the needle injection-valve is reduced below satisfactory practical limits.

Fuel-injection valves are known wherein the packing has been dispensed with, but the diameter of the needle-valve has of necessity had to be so small, in order that its area should be small enough to enable the spring to put a heavy load on it per square inch of area, that it has not been possible to produce the requisite fit between the needle-valve spindle and its guide to make it reasonably gasor oil-tight. r

This invention is to'overcome these obections to known types of fuel-injection valves in a practical way.

One object of the present invention is to construct a fuel-injection valve in which the needle valve is of such diameter that the bore in which the same operates may be readily formed by reaming, internal grinding or lapping.

Another object of the present invention is to render the use of the usual heavy spring for returning the needle valve to its position unnecessary, and utilize in place thereof an operating ram or piston having a pressure equalizing connection with the pressure existing at the entrance of the chamber controlled by the needle valve.

Still another object of the present invention is to provide a light spring at the top end of the ram or piston for keeping the understood by reference to the accompanying specification and drawing forming a part thereof, it being premised that changes may be made in the material employed and details of construction within the scope of the appended claims, without departing from the spirit of the invention.

Referring to the drawing, which illustrates in vertical central section an improved fuel injection valve according to the present invention, there is an upper part or pilot ram 1 and a needle valve proper or lower part 3 operatin respectively in the upper and lower cylin rical guides G and G It is essential to make the bore in the guide G in which the needle valve is to operate, of such size as to bring it within the practical possibility ofproducing a perfectly true bore by the usual commercial workshop processes of. reaming, internal grinding or lapping. The grinding and lapping of the needle valve s indle to make it a fluid-tight sliding fit in t e guide, then offers no' difiiculty, and the requisite fit for oil-tightness is easily obtained.

' formed that their abutting surfaces at 1 2 and 2 3 are parallel to one another and normal to the vertical axis of the parts 1, 2

and 3, z. e., normal to .the line in which all three parts reciprocate.

The upper end of the pilot ram 1, which serves as a piston'in the cylindrical guide G cooperates with a light spring LS kept 'in place by the screw S and gas tight'plug GP. The light spring LS tends normally to maintain the lower tapered end of the needle valve 3 in such position that it closes the fuel opening 0 leading into the engine cylinder, when there is no pressure in the system. a

In orderto dis ense with the heavy spring which'is or inarily required where a needle valve of large diameter is employed,

a the upper endof the pilot ram is connected by a pipe BC which maintains constant communication between the top end of the upper cylindrical guide G and the bottom of the lower cylindrical guide G This pipe is a pressure-equalizing conduit maintaimng a pressure on the pilot ram during the operation of the valve which counterbalances the rod and tends at all times to keep the needle valve shut and overcome friction and inertia forces in the ram and sure.

:v alve. The lower end of the pipe BC communicates with the interior of the cylindrical ide Gr by making a junction therewith at with the fuel-inlet conduits F and F leadingfrom the source of oil under presrains D and D are provided adjacent the' abutting surfaces of the upper and lower members with the intermediate pusher rod so as to drain from the cylinder any oil which leaks down the sides of the rod 1 orup the sides of the needle valve 3, The lower end of the cylindrical guide G and the upper end of thecylindrical guide G serve 1 respectively as guides for the upper and lower ends of'the-pusher rod which extend thereinto as shown.

- What I claim is:

1. For an oil engine, the combination with a needle valve com rising three parts, the upper part being of greater diameter than the lower part, and all the parts being separate from but abutting against one another, of a cylindrical guide in. which the lower part of the needle valve has a fluid-tight sliding fit and in which it serves as a piston controlling the admission of fuel to the engine, and a second cylindrical guide having a closed end and in which the upper part of said needle valve serves as a piston, a source of fuel under pressure, a conduitsupplying the fuel to the lower part of the needle valve in said first mentioned cylindrical guide and a pressure equalizing conduit extending therefrom to the upper part of the needle valve in said second mentioned cylindrical guide for equalizing the pressure on op-" posite sides of the needle valve, substan tially as described. v

2; For an oil engine, the combinationaccording to claim 1 in a form in which the needle valve is in three parts, the upper and lower parts being separate from but abut ting against the middle part, and all three parts so formed that their abutting surfaces the line inwhich all-the parts reciprocate, and guides for the upper and lower ends of the middle part, substantially as described.

3. In a fuel injection valve, the combination with a smaller guide constituting a cylinder, said cylinder having a fuel inlet are parallel to one another and normal to port situated atone end thereof and having a fuel passage leading to said port by way of the end of the cylinder adjacent thereto,

a larger cylindrical guide, a normally closed needle'valve controlling said port and arranged to open upwardly in a direction reverse to that of the flow of the fuel and having a two-diameter stem whereof the part of smaller diameter constitutes a piston in the smaller guide and the part of larger diameter constltutes a ram in saidlarger guide, of means for subjecting the end of said ram remote from said port to the downward fuel pressure that acts upwardly on the end of said piston adjacent to said port,

for the purpose specified.

In testimony whereof I have signed my name to this specification in the presence of two subscribin witnesses. I I IARL OTTO KELLER.

'Witnessesr v A. MITCHINSON, A. B'mzmmk 

